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csky: optimize memcpy_{from,to}io() and memset_io()
Optimize memcpy_{from,to}io() and memset_io() by transferring in 64 bit as much as possible with minimized barrier usage. This simplest optimization brings faster throughput compare to current byte-by-byte read and write with barrier in the loop. Code's skeleton is taken from the powerpc & arm64. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org>
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e4df2d5e85
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3 changed files with 103 additions and 1 deletions
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@ -31,6 +31,17 @@
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#define writel(v,c) ({ wmb(); writel_relaxed((v),(c)); mb(); })
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#define writel(v,c) ({ wmb(); writel_relaxed((v),(c)); mb(); })
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#endif
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#endif
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/*
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* String version of I/O memory access operations.
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*/
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extern void __memcpy_fromio(void *, const volatile void __iomem *, size_t);
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extern void __memcpy_toio(volatile void __iomem *, const void *, size_t);
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extern void __memset_io(volatile void __iomem *, int, size_t);
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#define memset_io(c,v,l) __memset_io((c),(v),(l))
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#define memcpy_fromio(a,c,l) __memcpy_fromio((a),(c),(l))
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#define memcpy_toio(c,a,l) __memcpy_toio((c),(a),(l))
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/*
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/*
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* I/O memory mapping functions.
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* I/O memory mapping functions.
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*/
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*/
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@ -2,7 +2,7 @@
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extra-y := head.o vmlinux.lds
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extra-y := head.o vmlinux.lds
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obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
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obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
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obj-y += power.o syscall.o syscall_table.o setup.o
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obj-y += power.o syscall.o syscall_table.o setup.o io.o
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obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
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obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
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obj-y += probes/
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obj-y += probes/
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91
arch/csky/kernel/io.c
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91
arch/csky/kernel/io.c
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@ -0,0 +1,91 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/export.h>
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#include <linux/types.h>
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#include <linux/io.h>
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/*
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* Copy data from IO memory space to "real" memory space.
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*/
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void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
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{
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while (count && !IS_ALIGNED((unsigned long)from, 4)) {
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*(u8 *)to = __raw_readb(from);
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from++;
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to++;
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count--;
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}
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while (count >= 4) {
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*(u32 *)to = __raw_readl(from);
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from += 4;
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to += 4;
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count -= 4;
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}
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while (count) {
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*(u8 *)to = __raw_readb(from);
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from++;
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to++;
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count--;
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}
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}
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EXPORT_SYMBOL(__memcpy_fromio);
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/*
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* Copy data from "real" memory space to IO memory space.
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*/
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void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
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{
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while (count && !IS_ALIGNED((unsigned long)to, 4)) {
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__raw_writeb(*(u8 *)from, to);
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from++;
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to++;
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count--;
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}
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while (count >= 4) {
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__raw_writel(*(u32 *)from, to);
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from += 4;
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to += 4;
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count -= 4;
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}
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while (count) {
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__raw_writeb(*(u8 *)from, to);
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from++;
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to++;
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count--;
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}
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}
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EXPORT_SYMBOL(__memcpy_toio);
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/*
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* "memset" on IO memory space.
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*/
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void __memset_io(volatile void __iomem *dst, int c, size_t count)
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{
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u32 qc = (u8)c;
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qc |= qc << 8;
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qc |= qc << 16;
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while (count && !IS_ALIGNED((unsigned long)dst, 4)) {
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__raw_writeb(c, dst);
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dst++;
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count--;
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}
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while (count >= 4) {
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__raw_writel(qc, dst);
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dst += 4;
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count -= 4;
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}
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while (count) {
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__raw_writeb(c, dst);
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dst++;
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count--;
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}
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}
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EXPORT_SYMBOL(__memset_io);
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